1. Field of the Invention
The present invention relates to fluid pressure actuated clamps, specifically multiple pressure actuated cylinders for machine vise jaws.
2. Description of Prior Art
Various fluid pressure actuated vises have been known in the prior art. For example, U.S. Pat. No. 4,223,879, issued to Ingo Wolf, and assigned to the same assignee as the present application, shows a hydraulic vise of basic design. The present application is an improvement to provide multiple, modular parallel operated additive load applying actuators for increasing clamping forces.
There have been multiple piston actuators such as that shown in U.S. Pat. No. 3,911,790, which are interlocked for operation.
U.S. Pat. No. 3,603 579 shows a vise that has a tandem operating movable jaw, utilizing both hydraulic and air pistons for final clamping of the movable jaw. The device, however, does not show modular, parallel operated, additive load applying cylinders, as with the present device.
U.S. Pat. No. 4,281,825 shows a manual hydraulically operated vise, with a bore formed in the vise body, and having an actuating piston. U.S. Pat. No. 4,070,.010 shows a vise that has a movable jaw operated with a fluid pressure cylinder and which has a pressure intensifier type piston operated in a second cylinder to increase the available pressure. The cylinders are not parallel acting. The intensifier boosts effective actuating pressure to the operating cylinders.
Additional patents which show multiple pistons but which operate in different manners in the present device are shown in U.S. Pat. Nos. 3,978,884; 3,968,735; 3,713,364; 3,057,205; and 2,415,783.
None of these patents show the concept of a pressure actuator which is adaptable to be easily mounted in a bore on an end wall of a vise and comprising a modular, multiple fluid pressure actuator that act together to provide additive force.